Color photography



adjacent emulsion layers undesired'color Patented June 16, 1942 UNITED STATES PATENT orr ce COLOR PHOTOGRAPHY Edith Weyde, Cologne-Riehl, and Erwin Trabert, Leverkusen-Wiesdorf, Germany, assignors,- by mesne assignments, to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware No' Drawing. Application August so, 1999, Serial I No. 292,608. In Germany September 2, 1938 "Our present invention relates 'toan improvement in color photography.

In multi-layer material used for the production of'color pictures by the process of color development there are used 'in the silver halide emulsions color formers, which are fast to diffusion 'and between the silver halide emulsion layers Our invention has for one object to provide a process of avoiding or diminishing this color fog. Another object of the invention is the provision of a process in which the color development is conducted in the presence of a substance which more easily oxidized than is the ,coupling component constituted by the developer substance.

Ithasbeen found that in the An additional object of the invention resides in theprovision of a process in which this reducing agent which hinders the formation of the fog isadded to the developer solution.

Yet another object of the invention is to provide a process in which this Ireducingagent is. incorporated to the emulsion layers, to the filter layers or in other layers or backings.

A further object of the invention consists in the provision of a process in which this reducing agent is added to the emulsion before the layer is cast.

Other objects of our invention will be seen from the following disclosure.

Suitable reducing agents are, for example, hy-

"droxylamine and its derivatives andorganic hydrazine compounds, for example phenylhydrazine sulfonic acid or phenylhydrazine carboxylic acid.

As developing substance there may be used para-phenylenediamine and its derivatives containing substituents in the nucleus or in oneor both amino groups or indeed both in the nucleus and in the amino group or groups; also paraaminophen'ols and their substitution products. The filter layers'comprising colloidal silver may ent No. 816,296. Besides the silver halide emulsion layers and filter layers other layers, for instance the antihalation layer (seeder instance French Patent No. 840,563) may be used for the addition of the reducing agent. The multi-layer material for color photography which is to be used in the invention may contain in the layers .be made for instance as described in French Pattions of suitable-developers:

Potassium blnmirlp 8 Claims. (01. 95-2) dyestufi' formers fastto difiusion such as are described in: U. S. applications Serial N o. 10, 04,

filed March 12, 1935, No. 111,250,.fi1ed Novem r 11, 1936, No. 72,718, filed Apr-114, 1936, No. 174,350,

filed November 13, 1937, No. 90,726, filed July 15, 1936, No. 94,340, filed August-5, 1936, No. 241,014,

filed November 17, 1938, No. 126,842, filed February 20, 1937, No. 158,860, filed Augustl3', 1937, No. 159,518, filed August 17, 1937, No. 164,499,

'filed September 18, 1937, No. 166,832,.filed October 1, 1937, No. 171,705, filed October 29, 1937, No. 171,701, filed October 29, 1937, No. 175,285,-filed November 18, 1937, No. 176,058, filed November 23, 1937, No. 191,952, filed February 23, 1938, No.

21, 1938, No. 254,235, filed February 2, 1939, No. 265,601, filed April 1, 1939, No, 265,758, filed April 3, 1939, 110. 265,759, filed April 3, 1939, N0.':284,250,

filed July 13, 1939, No. 284,257, filed July 13, 1939,

No. 284,258, filed July 13, 1939, U. S. Patents No.

2,156,821, dated May 2, 1939, No. 2,154,918; dated April 18, 1939, French Patent No. 844,928.

,Developer solutions containing the reducing agent may be used also for other photographic I materials inwhich the color picture is produced a by color development since byaddition of the reducing agent there is ,no ill effect produced on the action of the developer.

The following Examples 1, 2 and 3 are Example 1 Water I c 1000 Potassium carbonate. grams 50 yl-t ara-phenylenediamine; 1 3 Potassium bromide Example 2 Water c "1000 Potassium carbonate grams Diethyl-para-phenylenediamine do s do Hydroxylamine hydrochloride do Sodium sulfite sicc do Example 3 5 Water 1000 Potassiumcarbonate grams Diethyl-para phenylenediamine -do 3 Potassium bromide do 1 Phem'rlhydrazine-B-sulfonic-acid do 5 Example 4' To a photographic halide silver emulsion whic contains a color former fast to difiusion there are prescriprln 1 1 Hydroxylamine hydrochloride do 5 added per kilo of the emulsion 5 grams of paraphenylhydrazlne sulfonic acid.

Example 5 I An emulsion ofthe sparingly soluble lead salt of para-.phenylhydrazine carboxylic acid is made and then added to the colloidal silver solution which is to serve as a yellow filter.

We claim: 1. In a process of color developing a mum-layer substance in the developer which couples to form the color and of preventing formation of color fog during development of said material, between two adjacent emulsion layers a yellow filter carrying colloidal silver. I

5. A multi-layer material for color development comprising silver halide emulsion layers I containing color formers between two adjacent material, the several emulsion layers containing ment comprising silver halide emulsion layers containing color formers between two adjacent emulsion layers a yellow filter carrying colloidal silver, at least one of said layers containing a reducing agent capable of being more easily oxidized than is the substanc'e'in the developer which couples to form the color and of reventing formation of color fog during development of said material.

4. A multi-layer material for color develop- ,ment comprising silver halide emulsion layers containing color formers, at least one of said emulsion layers containing a reducing agent capable of being more easily oxidized than is the emulsion layers a yellow filter carrying colloidal silver, at least one of said filter layers containing a reducing agent capable of being more easily oxidized than isthe substance in the developer which couples to form the color and of preventing formation of color fog during development of said material.

6. A multi-layer material for color development comprising silver halide emulsion layers containing 'color' formers between two adjacent emulsion layers a yellow filter carrying colloidal silver, at least one of said layers containing hydroxylamine.

7. A multi-layer material for color development comprising silver halide emulsion layers containing color formers between two adjacent emulsion layers a yellow filter carrying colloidal silver, at

1 least one of said layers containing an organic hydrazine compound.

8. In a process of color-developing a multilayer material, the several emulsion layers containing color formers and located between two adjacent emulsion layers, a yellow filter layer carrying colloidal silver, the improvement which comprises conducting the color' development in the presence of a reducing agent selected from the class consisting of hydroxyl amines and organic hydrazine compounds.

v EDITH WEYDE.

ERWIN TRABERT, 

